/*
 * Copyright (C) 2018  niaoge<78493244@qq.com>
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.stategen.framework.generator.util;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.Map;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * The Class ClassHelpers.
 */
public class ClassHelpers {
    
    public static Class<?> getClazzIfCollection(Class<?> clazz){
        if (isArray(clazz)){
            return List.class;
        }
        
        if (Map.class.isAssignableFrom(clazz)){
            return Map.class;
        }
        
        return clazz;
    }
    
    public static boolean isArrayOrMap(Class<?> clazz){
        if (isArray(clazz)){
            return true;
        }
        
        if (Map.class.isAssignableFrom(clazz)){
            return true;
        }
        
        return false;
    }

    public static Object newInstance(Class<?> c) {
        try {
            return c.newInstance();
        } catch (Exception e) {
            throw new IllegalArgumentException("cannot new instance with class:" + c.getName(), e);
        }
    }

    public static Object newInstance(String className) {
        try {
            return newInstance(Class.forName(className));
        } catch (Exception e) {
            throw new IllegalArgumentException("cannot new instance with className:" + className, e);
        }
    }

    public static ClassLoader getDefaultClassLoader() {
        ClassLoader cl = null;
        try {
            cl = Thread.currentThread().getContextClassLoader();
        } catch (Throwable ex) {
            // Cannot access thread context ClassLoader - falling back to system class loader...
        }
        if (cl == null) {
            // No thread context class loader -> use class loader of this class.
            cl = ClassHelpers.class.getClassLoader();
        }
        return cl;
    }

    /**
     *  
     * 取得某个接口下所有实现这个接口的类 .
     *
     * @param c the c
     * @return the all class by interface
     */
    public static List<Class<?>> getAllClassByInterface(Class<?> c) {
        List<Class<?>> returnClassList = null;

        if (c.isInterface()) {
            // 获取当前的包名  
            String packageName = c.getPackage().getName();
            // 获取当前包下以及子包下所以的类  
            List<Class<?>> allClass = getClasses(packageName);
            if (allClass != null) {
                returnClassList = new ArrayList<Class<?>>();
                for (Class<?> clz : allClass) {
                    // 判断是否是同一个接口  
                    if (c.isAssignableFrom(clz)) {
                        // 本身不加入进去  
                        if (!c.equals(clz)) {
                            returnClassList.add(clz);
                        }
                    }
                }
            }
        }

        return returnClassList;
    }

    /**
     * 取得某一类所在包的所有类名 不含迭代.
     *
     * @param classLocation the class location
     * @param packageName the package name
     * @return the package all class name
     */
    public static String[] getPackageAllClassName(String classLocation, String packageName) {
        //将packageName分解  
        String[] packagePathSplit = packageName.split("[.]");
        String realClassLocation = classLocation;
        int packageLength = packagePathSplit.length;
        for (int i = 0; i < packageLength; i++) {
            realClassLocation = realClassLocation + File.separator + packagePathSplit[i];
        }
        File packeageDir = new File(realClassLocation);
        if (packeageDir.isDirectory()) {
            String[] allClassName = packeageDir.list();
            return allClassName;
        }
        return null;
    }

    /**
     *  
     * 从包package中获取所有的Class .
     *
     * @param packageName the package name
     * @return the classes
     */
    public static List<Class<?>> getClasses(String packageName) {

        //第一个class类的集合  
        List<Class<?>> classes = new ArrayList<Class<?>>();
        //是否循环迭代  
        boolean recursive = true;
        //获取包的名字 并进行替换  
        String packageDirName = packageName.replace('.', '/');
        //定义一个枚举的集合 并进行循环来处理这个目录下的things  
        Enumeration<URL> dirs;
        try {
            dirs = Thread.currentThread().getContextClassLoader().getResources(packageDirName);
            //循环迭代下去  
            while (dirs.hasMoreElements()) {
                //获取下一个元素  
                URL url = dirs.nextElement();
                //得到协议的名称  
                String protocol = url.getProtocol();
                //如果是以文件的形式保存在服务器上  
                if ("file".equals(protocol)) {
                    //获取包的物理路径  
                    String filePath = URLDecoder.decode(url.getFile(), "UTF-8");
                    //以文件的方式扫描整个包下的文件 并添加到集合中  
                    findAndAddClassesInPackageByFile(packageName, filePath, recursive, classes);
                } else if ("jar".equals(protocol)) {
                    //如果是jar包文件   
                    //定义一个JarFile  
                    JarFile jar;
                    try {
                        //获取jar  
                        jar = ((JarURLConnection) url.openConnection()).getJarFile();
                        //从此jar包 得到一个枚举类  
                        Enumeration<JarEntry> entries = jar.entries();
                        //同样的进行循环迭代  
                        while (entries.hasMoreElements()) {
                            //获取jar里的一个实体 可以是目录 和一些jar包里的其他文件 如META-INF等文件  
                            JarEntry entry = entries.nextElement();
                            String name = entry.getName();
                            //如果是以/开头的  
                            if (name.charAt(0) == '/') {
                                //获取后面的字符串  
                                name = name.substring(1);
                            }
                            //如果前半部分和定义的包名相同  
                            if (name.startsWith(packageDirName)) {
                                int idx = name.lastIndexOf('/');
                                //如果以"/"结尾 是一个包  
                                if (idx != -1) {
                                    //获取包名 把"/"替换成"."  
                                    packageName = name.substring(0, idx).replace('/', '.');
                                }
                                //如果可以迭代下去 并且是一个包  
                                if ((idx != -1) || recursive) {
                                    //如果是一个.class文件 而且不是目录  
                                    if (name.endsWith(".class") && !entry.isDirectory()) {
                                        //去掉后面的".class" 获取真正的类名  
                                        String className = name.substring(packageName.length() + 1, name.length() - 6);
                                        try {
                                            //添加到classes  
                                            classes.add(Class.forName(packageName + '.' + className));
                                        } catch (ClassNotFoundException e) {
                                            e.printStackTrace();
                                        }
                                    }
                                }
                            }
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

        return classes;
    }

    /**
     *  
     * 以文件的形式来获取包下的所有Class .
     *
     * @param packageName the package name
     * @param packagePath the package path
     * @param recursive the recursive
     * @param classes the classes
     */
    public static void findAndAddClassesInPackageByFile(String packageName, String packagePath, final boolean recursive, List<Class<?>> classes) {
        //获取此包的目录 建立一个File  
        File dir = new File(packagePath);
        //如果不存在或者 也不是目录就直接返回  
        if (!dir.exists() || !dir.isDirectory()) {
            return;
        }
        //如果存在 就获取包下的所有文件 包括目录  
        File[] dirfiles = dir.listFiles(new FileFilter() {
            //自定义过滤规则 如果可以循环(包含子目录) 或则是以.class结尾的文件(编译好的java类文件)  
            public boolean accept(File file) {
                return (recursive && file.isDirectory()) || (file.getName().endsWith(".class"));
            }
        });
        //循环所有文件  
        for (File file : dirfiles) {
            //如果是目录 则继续扫描  
            if (file.isDirectory()) {
                findAndAddClassesInPackageByFile(packageName + "." + file.getName(), file.getAbsolutePath(), recursive, classes);
            } else {
                //如果是java类文件 去掉后面的.class 只留下类名  
                String className = file.getName().substring(0, file.getName().length() - 6);
                try {
                    //添加到集合中去  
                    classes.add(Class.forName(packageName + '.' + className));
                } catch (ClassNotFoundException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    
    public static boolean  isArray(Class<?> clz){
        return List.class.isAssignableFrom(clz) ||clz.isArray();
    }
}
